HTTP endpoints cleanup (#13251)

* remove validation package

* structs cleanup

* merge with apimiddleware removal

* more validation and Bls capitalization

* builder test fix

* use strconv for uint->str conversions

* use DecodeHexWithLength

* use exact param names

* rename http package to httputil

* change conversions to fmt.Sprintf

* handle query paramsd and route variables

* spans and receiver name

* split structs, move bytes helper

* missing ok check

* fix reference to indexed failure

* errors fixup

* add godoc to helper

* fix BLS casing and chainhead ref

* review

* fix import in tests

* gzl

network/httputil/reader_test.go

@@ -0,0 +1,88 @@
+package httputil
+
+import (
+	"fmt"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v4/api"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+)
+
+func TestSSZRequested(t *testing.T) {
+	t.Run("ssz_requested", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{api.OctetStreamMediaType}
+		result := SszRequested(request)
+		assert.Equal(t, true, result)
+	})
+
+	t.Run("ssz_content_type_first", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s", api.OctetStreamMediaType, api.JsonMediaType)}
+		result := SszRequested(request)
+		assert.Equal(t, true, result)
+	})
+
+	t.Run("ssz_content_type_preferred_1", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s;q=0.9,%s", api.JsonMediaType, api.OctetStreamMediaType)}
+		result := SszRequested(request)
+		assert.Equal(t, true, result)
+	})
+
+	t.Run("ssz_content_type_preferred_2", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s;q=0.95,%s;q=0.9", api.OctetStreamMediaType, api.JsonMediaType)}
+		result := SszRequested(request)
+		assert.Equal(t, true, result)
+	})
+
+	t.Run("other_content_type_preferred", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s;q=0.9", api.JsonMediaType, api.OctetStreamMediaType)}
+		result := SszRequested(request)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("other_params", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{fmt.Sprintf("%s,%s;q=0.9,otherparam=xyz", api.JsonMediaType, api.OctetStreamMediaType)}
+		result := SszRequested(request)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("no_header", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		result := SszRequested(request)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("empty_header", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{}
+		result := SszRequested(request)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("empty_header_value", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{""}
+		result := SszRequested(request)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("other_content_type", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{"application/other"}
+		result := SszRequested(request)
+		assert.Equal(t, false, result)
+	})
+
+	t.Run("garbage", func(t *testing.T) {
+		request := httptest.NewRequest("GET", "http://foo.example", nil)
+		request.Header["Accept"] = []string{"This is Sparta!!!"}
+		result := SszRequested(request)
+		assert.Equal(t, false, result)
+	})
+}